Sighting devices have long been used in conjunction with weapons and firearms, such as rifles, handguns, and crossbows, to allow a shooter to accurately aim and shoot at a selected target. The accuracy of a shot can be affected by variations in shooting conditions such as bullet and arrow trajectory, wind conditions, distance to the target, and lighting conditions. To compensate for these variations and improve the accuracy of a shot, some sighting devices provide controls to allow a shooter to make incremental adjustments to the optical characteristics or location of aiming marks of the sighting device.
Typically, such adjustments are made using rotatable adjustment knobs that actuate an adjustable member of the sighting device. Knobs that adjust the relative alignment between an optical path and a crosshair (or a reticle) are known as “elevation” and “windage” controls, for adjusting respective vertical and horizontal aim. Rotatable knobs may also be used to adjust other features of riflescopes, binoculars, spotting scopes, or other suitable optical devices, such as parallax, focus, reticle illumination intensity, reticle type, or other suitable features.
Some sighting devices or other devices include adjustment knobs with internal battery compartments for retaining a battery that powers electronics or lighting associated with the device or a weapon on which the device is mounted. For example, rotatable knobs with internal battery compartments may be used in various configurations for activating or adjusting the brightness of an illuminated reticle. In some riflescopes, for example, an on/off/brightness adjustment knob is positioned on a main tube of a sight housing. Other riflescopes have an on/off switch activated by pulling a parallax adjustment knob. Typically, for these knobs, a battery cap is provided that screws onto the end of the knob for closing and sealing the battery compartment from water and moisture. Rotation of a screw-on cap, however, may also inadvertently twist the knob and change the adjustment setting.
Conventional screw-on battery caps are often cumbersome to twist on and off because the fine screw threads used are sometimes difficult for a user to properly align. Also, a small bladed tool or screwdriver is usually needed for loosening and unscrewing the battery cap from the adjustment knob. Moreover, once removed, screw-on battery caps can easily be dropped or misplaced.
It is known to add a retention strap or cord to tether a screw-on battery cap to the housing of the adjustment knob or the main tube. However, these retention straps are prone to snagging and catching on other objects, or the retention straps may fray or break. Furthermore, retention straps will occasionally bind the screw-on battery covers or otherwise make the cover more cumbersome to twist on and off from the adjustment knob. Retention straps also hinder rotational adjustment of the knob, making it more difficult to activate, adjust, or precisely control associated electronics settings.